GPU Usage Randomly Dropping (Please Help!)

[tuberolector]

In games, after about a minute of playing, my GPU usage will randomly drop from 85-100% to 50-60%. This causes a massive drop in FPS and makes some games unplayable. This does not just happen in 1 or 2 games. Every game that I have tried has this issue. I also just revived my GPU back from the manufacturer after sending it in for a completely different reason.

 

Considering that the drops might not have been an issue with the GPU, today I purchased a second Radeon HD 7950 to use in Crossfire with the one I already had. When I play games with Crossfire enabled, however, the GPU uage does not exceed 40%, giving me lower FPS than with just one card. 

 

This is really bothering me and making me worry that I will have to spend even more money on completely new GPUs. Any help would be GREATLY appreciated. 

 

Anything I've already tried:

-Reinstalling the drivers

-Removing GPU overclocks

 

Other System Specs:

GPU: Sapphire AMD Radeon HD 7950 (x2)

CPU: Intel Core i7-4790k (@ 4.6 Ghz)

RAM: 8 GB 1600 Mhz

Motherboard: Gigabyte Z97MX-Gaming 5

Power Supply: EVGA Supernova 850 B2

 

[JRuss16]

you could be runing out of VRAM

[Nico123473]

Temps? It could be thermal throttling